Bone diseases Flashcards

1
Q

Achondroplasia: what is it?

A

Failure of longitudinal bone growth -> short limbs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Achondroplasia: what kind of ossification is affected, and which is not affected?

A

Endochondral ossification is affected -> short limbs

Membranous ossification intact -> relatively big head

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Achondroplasia: which protein is affected? Which cells are affected?

A

Constitutive activation of Fibroblast growth factor receptor 3 (FGFR3) -> inhibits chondrocytes proliferation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Achondroplasia: what percentage of mutations occur sporadically (during spermatogenesis?

A

85%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Achrondroplasia: genetics?

A

Autosomal dominant with full penetrance (homozygoty is lethal)

85% of mutations occur sporadically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Achondroplasia: risk factor?

A

High paternal age

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the most common cause of short-limbed dwarfism?

A

Achrondroplasia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Osteoporosis: what is it?

A

Loss of bone mass, both cortical and trabecular, despite normal bone mineralization and lab values

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Osteoporosis: lab values of calcium and phosphate?

A

Normal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Osteoporosis: most common cause?

A

Low estrogen levels and old age: increased bone resorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Osteoporosis: can be secondary to which conditions?

A

Hyperparathyreodism
Hyperthyreodism
Multiple myeloma
Malabsorption syndromes
Anorexia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Osteoporosis: can be secondary to which medications?

A

Steroids
Alcohol
Anticonvulsants
Anticoagulants
Thyroid replacement therapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Osteoporosis: how to diagnose?

A

DEXA-scan (lumbar spine, total hip and femoral neck with a T-score of -2.5)

OR

Fragility fracture (fall from standing height, minimal trauma)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Osteoporosis: when to screen?

A

1x in females >65

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Osteoporosis: prophylaxis?

A

Regular weight bearing exercise, adequate calcium and vit D intake throughout adulthood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Osteoporosis: DEXA of what and which values?

A

Lumbar spine, total hip, femoral neck. T-score <2.5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Osteoporosis: treatment?

A

Biphosphonate

Other:
- Teriparatide (synthetic PTH, promotes osteoblast survival)
- SERM (selective estrogen receptor modulators)
- Rarely calcitonin, denosumab (monoclonal antibody against RANKL)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Osteoporosis: complication?

A

Vertebral compression fracture: acute back pain, loss of height, kyphosis

Can also present with fractures of femoral neck and distal radius

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is a fracture of the distal radius?

A

Colles fracture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Colles fracture

A

Fracture of distal radius

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is loss of bone mass with normal mineralization and lab values?

A

Osteoporosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Osteopetrosis: what is it?

A

Failure of bone resorption -> thickened dense bones that are prone to fracture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Osteopetrosis: which cells are defective?

A

Osteoclasts (failure of bone resorption)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Osteopetrosis: underlying pathophysiology

A

Mutations impair osteoclasts to generate acidic environment

Acidic environment is needed for bone resorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Osteopetrosis: what happens to the bone marrow?

A

Overgrowth of bone fills marrow space -> pancytopenia, extremedullary hematopoiesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Osteopetrosis: lab values of blood cells?

A

Pancytopenia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Osteopetrosis: complication?

A

Cranial nerve impingement and palsies due to narrowed foramina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Osteopetrosis: x-ray?

A

Diffuse symmetric sclerosis

29
Q

Osteopetrosis: treatment?

A

Bone marrow transplant curative due as osteoclasts are derived from monocytes

30
Q

Thickened, dense bones that are bone to fracture. Which disease?

A

Osteopetrosis

31
Q

Failure of bone resorption. Which disease?

A

Osteopetrosis

32
Q

Which disease has defective osteoclasts and failure of bone resorption?

A

Osteopetrosis

33
Q

Osteomalacia: pathophysiology?

A

Defective mineralization of osteoid (adults)

34
Q

Rickets: pathophysiology?

A

Defective mineralization of cartilaginous growth plate (children)

35
Q

Osteomalacia/rickets: most common cause?

A

Vit D deficiency

Leads to defective mineralization

36
Q

Osteomalacia/rickets: pathophysiology?

A

Defective mineralization (due to Vit D deficiency)

37
Q

Osteomalacia: x-ray?

A

Osteopenia and pseudofractures (Looser zone/Milkman lines)

38
Q

Rickets: x-ray?

A

Epiphyseal widening and metaphyseal cupping/fraying

39
Q

Children with rickets: symptoms?

A

Pathological bow legs (genu varum)
Beadlike costochondral junctions (rachitic rosary)
Craniotabes (soft skulls)

40
Q

Genu varum, rachitis rosary, craniotabes. Which disease?

A

Rickets

(defective mineralization due to vit D deficiency)

41
Q

Pathological bow legs, beadlike costochondral junctions and a soft skull. Which disease?

A

Rickets

(defective mineralization due to vit D deficiency)

42
Q

What does Vit D deficiency (osteomalacia/rickets) do to calcium, PTH and phosphate?

A

Vit D low -> serum calcium decreases -> PTH secretion increases -> serum phosphate decreases

Vit D helps calcium resorption

43
Q

What happens to osteoblast activity in osteomalacia/rickets?

A

Osteoblast activity increases
ALP also increases

44
Q

Osteotis deformans: other name?

A

Paget’s disease

45
Q

Paget’s disease: other name?

A

Osteitis deformans

46
Q

Osteitis deformans/Paget: pathophysiology

A

Localized disorder of bone remodeling

caused by increased osteoclastic activity
followed by increased osteoblastic activity, forms poor quality bone

47
Q

Osteitis deformans/Paget: what is wrong with the bone?

A

Remodeling is of poor quality

48
Q

Osteitis deformans/Paget: which cells are affected?

A

Increased activity osteoclasts

Followed by increased activity osteoblasts, forms poor quality bone

49
Q

Osteitis deformans/Paget: lab values?

A

Calcium, phosphate and PTH normal

ALP increased

50
Q

Osteitis deformans/Paget: what are the levels of calcium, phosphate and PTH?

A

normal

51
Q

Osteitis deformans/Paget: what is the lab value of ALP?

A

Increased

52
Q

Osteitis deformans/Paget: histology?

A

Mosaic pattern of woven and lamellar bone (osteocytes within lacunae in chaotic juxtapositions)

53
Q

Osteitis deformans/Paget: fracture?

A

Long bone chalk stick fractures

54
Q

Osteitis deformans/Paget: complications?

A

Heart failure (due to arteriovenous shunts)
Osteosarcoma
Hearing loss

55
Q

Osteitis deformans/Paget: increased risk of which malignity?

A

Osteosarcoma

56
Q

Osteitis deformans/Paget: what can happen to skull?

A

Hat size increase due to skull thickening

57
Q

Which disease can increase hat size?

A

Osteitis deformans/Paget, due to thickening of the skull

58
Q

Stages of Paget diseas?

A

Early destructive (lytic): osteoclasts
Intermediate (mixed): osteoclasts and blasts
Late (sclerotic/blastic): osteoblasts

59
Q

Can osteitis deformans/Paget enter a quiescent phase?

A

Yes

60
Q

Osteitis deformans/Paget: treatment?

A

Biphosphonates (inhibit osteoclasts)

61
Q

What do biphosphonates do?

A

Inhibit osteoclasts

62
Q

Which bone disease can cause hearing loss?

A

Osteitis deformans/Paget

63
Q

Avascular necrosis of bone: what is it?

A

Infarction of bone and marrow, very painful

64
Q

Avascular necrosis: most common site?

A

Femoral head (watershed zone between medial femoral circumflex and branch of obturator artery)

65
Q

Mnemonic avascular necrosis?

A

CASTS Bend LEGS

65
Q

Between which arteries the watershed zone of the femoral head?

A

Medial femoral circumflex
Branch of obturator artery

66
Q

Causes of avascular necrosis?

A

CASTS Bend LEGS

C orticosteroids
A lcohol (chronic)
S ickle cell disease
T rauma
S LE

B ‘the Bends’
e
n
d

LE ggs-Calve-Perthes
G aucher
S lipped capital femoral epiphysis

67
Q
A